Author Topic: Aerojetís confidence in Next Generation Engine and green propellants  (Read 17437 times)

Offline strangequark

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What's wrong with carbon?

Can't be used for monopropellant because of carbon deposits on the catalyst pack.

Well yes, but it's also a contaminant if you're searching for life.

Offline deltaV

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Thanks, the theory of not wanting to contaminate the landing site with carbon compounds makes sense to me.

Offline robertross

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Good timing! ;D

NASA SEEKS PROPOSALS FOR GREEN PROPELLANT TECHNOLOGY DEMONSTRATIONS

...
NASA anticipates making one or more awards in response to this
solicitation, with no single award exceeding $50 million. Final
awards will be made based on the strength of proposals and
availability of funds. The deadline for submitting proposals is April
30.
Indeed.
Nice to see Aerojet ahead of the curve on this. Never hurts to get funding for your work.
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline Steven Pietrobon

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I don't think N2O/C2H6O is a very good combination. Liquid N2O can detonate under shock, as Scaled Composites found out to its loss. Compared to liquid oxygen it does give better density, but much worse Isp. Here's some numbers. The impulse density (Id) is propellant density times exhaust speed, and gives an indication of the volumetric efficiency of the propellant. The higher the better.

Efficiency = 97.4%
Chamber Pressure = 20.7 MPa
Expansion Ratio = 77.5
HTP = 0.98*H2O2 + 0.02*H2O by mass

Propellants  MR   dp (kg/L)  ve (m/s) Id (Ns/L)
O2/RPĖ1      2.8   1.0307     3554     3663
N2O/RP-1     9.2   1.1626     3099     3603
N2O/C2H6O    5.7   1.1301     3042     3438
HTP/RPĖ1     7.3   1.3059     3223     4209


HTP has excellent Id which makes it a very good first stage propellant, better even than O2/RPĖ1. Modern HTP is stable and decomposes at less than 1% per year. It also does not detonate under shock, but cleanliness to the same levels as for O2 are required to prevent rapid decomposition.

For your amusement, attached is a list I've made up of various propellant combinations. Have a favourite that's not listed? Let me know and I'll run the numbers.
« Last Edit: 02/11/2012 06:48 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Ronsmytheiii

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Bumping as related to MSL, but also would be interested to know how Aerojet will handle the NGE competition now that their main competitor was purchased by their parent company.....
"Every vision is a joke until the first man accomplishes it; once realized, it becomes commonplace." - Robert Goddard

Offline strangequark

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Bumping as related to MSL, but also would be interested to know how Aerojet will handle the NGE competition now that their main competitor was purchased by their parent company.....

My understanding is that PWR's entry was essentially the RL-10C. It wouldn't surprise me if the RL-10C ends up being used in the near-term, with Aerojet's NGE coming online later on. The development on the former should be quick, whereas the latter offers a lot more performance for the longer term, but it's a completely novel engine cycle.

Offline baldusi

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My understanding is that PWR's entry was essentially the RL-10C. It wouldn't surprise me if the RL-10C ends up being used in the near-term, with Aerojet's NGE coming online later on. The development on the former should be quick, whereas the latter offers a lot more performance for the longer term, but it's a completely novel engine cycle.
That means lots and lots of qual testing, thus expense and time?

Offline strangequark

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That means lots and lots of qual testing, thus expense and time?

Si, por supuesto.

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